Earth drilling operations typically include provision for a blast of pressurized air to be directed downwardly through an axial through bore in an elongated drill string and thence upwardly through the annular space between the drill string and the walls of the bore hole to remove cuttings or chips from the bore hole as drilling progresses. The force of the pressurized air stream ejects the cuttings from the bore hole with sufficient force and velocity that the cuttings can be a danger to workers in the immediate area. In addition, the accumulation of ejected cuttings around the bore hole entry presents a significant cleanup problem, a safety hazard, and an inconvenience to drilling operations. These conditions are no less of a problem for drilling operations which utilize a liquid flushing medium such as water or drilling mud rather than a pressurized air stream to clear cuttings from the bore hole.
In the earth drilling arts it is well known to provide a diverter apparatus in the form of a generally cylindrical elongated sleeve or skirt structure positioned generally coaxially with respect to the drilling axis and thus encompassing the bore hole entry. A diverter apparatus typically engages the ground in surrounding relationship with the bore hole entry to thereby protect workers in the immediate area from the flying cuttings or chips ejected from the bore hole, and to divert such cuttings away from the bore hole entry via a diverter coupling to a remote location for ultimate disposal of the cuttings.
There are known in the art a variety of sludge removal bonnets, dust collecting devices, and otherwise characterized diverter assemblies for rock drills and other drilling apparatus. Such known diverters commonly have been carried by a mobile or portable drilling apparatus for selective movement thereof into engagement with an area surrounding the location of the bore hole to provide the desired diverter capability during drilling operations. For example, Swiss Pat. No. 407,855 appears to disclose a corrugated skirt of sorts which is positioned about a bore hole entry to provide a space about the bore hole from which cuttings may be directed by way of a diverter connection. U.S. Pat. No. 3,499,641 discloses a fluid pressure actuated, diaphragm type clamping device which, under the impetus of fluid pressure,is moved into clamping engagement with a workpiece for drilling thereof. Other patents relating generally to diverter apparatus include U.S. Pat. Nos. 3,033,298, 3,924,696, 4,321,975, 4,444,280, 3,417,830, and 4,440,243, as well as Russian Pat. No. 466,342.
The prior art as above characterized includes diverter structures which are carried by a drilling apparatus and are movable by suitable motive means selectively into or out of engagement with a surface area encompassing the bore hole entry so that the diverter may be quickly and efficiently placed for drilling operations, and just as easily withdrawn when it is desired to move the drilling rig from one drilling site to another. This is especially important for mobile drills as it is not economical or convenient in mobile drill operations to set and cement a conductor pipe for each bore hole drilled in order to accommodate cuttings removal from the bore hole. It is, however, just as necessary for portable or mobile drilling rigs as for others to have available the above characterized cuttings diverting capability in order to ensure efficient and safe drilling operations.
Practitioners of the art thus have continually sought improved apparatus for providing diverter capability, especially for portable drills in drilling operations which require convenient mobility for movement of the drill frequently from one drilling site to another.